The five primary topics of investigation in the proposal include the following: 1. We propose to continue our attempts to inject tritiated amino acids into the cell bodies of sensory neurons in the trigeminal ganglion of cats in order to identify their peripheral termination and their termination in the trigeminal nucleus in the cord. 2. We propose to chart the termination in the trigeminal nucleus of fibers in the trigeminal ganglion with functionally discrete characteristics. The same methods described in 1 will be used. Fibers with a nociceptive function will be emphasized. 3. Since localized evoked responses have been recorded through scalp electrodes to thermal stimulation of the hand of humans we propose to search SI of the rhesus cortex for single cells which responds to thermal stimulation, preferably of the hand. 4. We propose to measure the return of tactile, thermal and pain sensations to grafted skin in order to determine the pattern of the returning sensation, the best method of grafting to insure return of sensation, and more particularly to provide some indication of the meaning of standard neurological tests in terms of nervous function. 5. We propose to continue our measurements of (a) measurement of warm and cool sensitivity in humans as a function of adapting temperature by signal detection methods; (b) measurement of the growth of sensation by magnitude estimates of the increasing intense warm and cool stimuli as a function of skin adapting temperature, rate of temperature change, and the skin area stimulated.